The present invention relates to apparatus for sampling a source of compressed gas and to a method of obtaining a sample of such gas.
Compressed gas is used in a wide range of environments as a convenient source of supply for breathing gas. There is therefore a requirement to analyze routinely the gas to ensure the purity of the gas and to ensure the safety of the user.
The purity of the compressed breathing gases in question may only be determined by laboratory analysis. This necessitates the collection of representative samples of the gas at the site of its use with subsequent shipment of the samples to a laboratory for comprehensive analysis. Such a comprehensive analysis is relatively complex requiring the services of a competent analytical laboratory, and there is difficulty in obtaining representative samples of the gas for the determination of contaminants such as oil mist, particulate matter and water.
The present techniques applied to breathing gases sampling and analysis require samples of the gas to be collected in pressure vessels which are then shipped to a central analytical laboratory for complete analysis of the contents.
This however presents a hazard associated with handling and shipping of high pressure gas samples and only provides a limited volume of sample for oil mist, water or trace aerosol contaminant detection. Further the accuracy of the results associated with analyzing the contents of a pressure vessel for oil mist or water are uncertain due to the tendency of these constituents to condense out on the wall of the pressurised sampling vessel and the initial cost and continuing maintenance by cleaning the pressure vessel makes the cost of this form of analysis high.
It is therefore an object of the present invention to obviate or mitigate the above disadvantages.